Abstract

Notch sensitivity, free edge delamination and brittle failure are limiting factors for the wider use of conventional composite laminates. In our previous study, a hybrid layup concept with the different materials blocked together but with dispersed orientations was successfully used to design pseudo-ductile hybrid composites with no free-edge delamination. This study introduces a comprehensive set of designed and characterised orientation-dispersed pseudo-ductile thin-ply hybrid composites to address notch sensitivity, another important limiting factor in conventional composite laminates. Un-notched, open-hole and sharp notched tension tests were performed on three different thin-ply carbon/glass hybrid configurations. The investigated laminates showed a successful pseudo-ductile un-notched behaviour with improved notch-insensitivity and suppression of free-edge delamination that was an undesirable damage mode in previously investigated hybrids with plies of the same orientation blocked together. This notch insensitivity results from subcritical damage in the laminates due to the pseudo-ductile damage mechanisms, i.e. dispersed delamination and fragmentation. These damage mechanisms can eliminate stress concentrations near the notch and suppress the conventional damage mechanisms that govern the notched response of the laminates.